Today I've got a pretty tall cake again. This one is 6 layers of cake, so I decided to put dowels and cardboard cut to size between each 3 layers of cake. No matter how hard I try, whenever I have these tall type cakes, I see the indentation on the fondant the entire way around the cake where the cake board is located. Does anyone have any hints as to help hide this? I'm using buttercream under my fondant.
Thanks!

Make sure to let the cake settle after you fill it overnight. Use cake spackle to fill the area where the board is going so it will be smooth with the sides of the cake. Spackle is just cake crumbs mixed with icing to make a paste to fill spots. Good luck.

Thanks for the advice Donnagardner! I only had a little cake leftover to try the spackle and it was a huge help!